Oxidation is one of the most fundamental transformations in organic synthesis and there are numerous methods reported in the literature. (Hudlicky, M. "Oxidations In Organic Chemistry", ACS Monograph No. 186 American Chemical Society Washington D.C. (1990).) However, relatively few methods exist for the oxidation of primary alcohols to the corresponding carboxylic acids. The most commonly used ones are CrO.sub.3 /H.sub.2 SO.sub.4 (Bowden; Heilbron; Jones; Weedon J. Chem. Soc., 1946, 39; Bowers; H.; Jones; L. J. Chem. Soc., 1953, 2548; Millar, J.G.; Oehlschlager, A.C.; Wong, J.W. J. Org. Chem. 1983, 48, 4404.), RuCl.sub.3 /H.sub.5 IO.sub.6 (Carlsen, P.H.J.; Katsuki, T.; Martin V.S.; Sharpless, K.B. J. Org. Chem. 1981, 46, 3936.) and TEMPO/NaClO (Nooy, A.E.J. de; Besemer, A.C.; Bekkum, H. v. Synthesis, 1996, 1153.; Anelli, P.L.; Biffi, C.; Montanari, F.; Quici, S. J. Org. Chem. 1987,52, 2559.; Miyazawa, T.; Endo, T.; Shiihashi, S.; Okawara, M. J. Org. Chem. 1985, 50, 1332). A two-step process involving Swern oxidation (Mancuso, A.J.; Huang, S-L., Swern, D. J. Org. Chem. 1978,43, 2480.; Mancuso, A.J.; Brownfan, D.S.; Swern, D. J. Org. Chem. 1979,44, 4148.; Ireland, R.; Norbeck, D. J. Org. Chem. 1985,50, 2198.) followed by oxidation of the resulting aldehyde with NaClO.sub.2 (Lindgren, B.O.; Nilsson, T. Acta Chem. Scand. 1973,27, 888.; Dalcanale, E.; Montanari, F. J. Org. Chem. 1986, 51, 567) is another option. All of these procedures have some limitations and disadvantages and new methods for the oxidation of primary alcohols to the carboxylic acids are still desired. (Schroder, M.; Griffith, W.P. J. Chem. Soc. Chem. Comm. 1979, 58.; and Paquette, L.A.; Dressel, J.; Pansegrau, P.D. Tetrahedron Lett. 1987,28,4965.)
The present invention relates to an oxidation using sodium chlorite in the presence of a catalytic amount of TEMPO and sodium hypochlorite which converts a primary alcohol to a carboxylic acid. This oxidation method avoids the disposal issues associated with running a Jones oxidation (CrO.sub.3 /H.sub.2 SO.sub.4) reaction, as well as reducing the epimerization of any .alpha.-chiral centers and is a one step procedure. For substrates prone to chlorination with the TEMPO-NaClO protocol, the present invention reduces this problem.